Publication and Dissemination of Results in Clinical Trials in Neurology

Objective ClinicalTrials.gov is an online database used to register and track clinical trials. Previous studies of this database have revealed low publication rates and selective reporting of results for registered trials. This study sought to classify the types of neurology studies within this registry and characterize both publication rates and time to publication.

Design We performed a search on July 19, 2016, using the ClinicalTrials.gov registry category “nervous system disease” to identify completed interventional studies conducted in the United States between October 1, 2007, and July 1, 2014. We then used both ClinicalTrials.gov and SCOPUS, the largest peer review journal database, to classify the topic subcategory and publication status as of December 2016. The primary outcomes were publication of results in a scientific journal and the time from study completion to publication. Publication status was identified through ClinicalTrials.gov entries as well as systematically searching SCOPUS with key terms for the primary investigator, condition, and intervention. Secondary outcome was the dissemination of results through ClinicalTrials.gov.

Results In all, 2072 studies were identified. Most funding came from industry (50.7%; n = 1051) or other nongovernmental sources (54.1%; n=1121), with only 12.9% of studies receiving National Institutes of Health funding (n = 267) and 7.1% receiving other US federal funding (n = 148). Of the 10 subcategories, the most prevalent was “pain medicine,” which accounted for 28.3% (n = 586) of all studies, followed by “behavioral/neuropsychiatry” (17.7%; n = 367) and “neuromuscular medicine” (13.8%; n = 285). The overall publication rate was 47.8% (n = 990), with subcategory rates ranging from 38.8% (69 of 172) for “sleep medicine,” to 54.0% (154 of 285) for “neuromuscular medicine.” The median (SD) time to publication was 25 (15.2) months, with significant differences in time to publication among subcategories (P = .003). “Vascular neurology” had the fastest time to publication (median [SD], 18 [13.7] months) and was significantly faster than “pain medicine” (25 [15.6] months,P = .029), “behavioral‎/neuropsychiatry” (27 [16.5] months,P = .002), and “epilepsy’” (28 [17.0] months,P = .01) on follow-up testing. Results were reported through ClinicalTrials.gov for only 40.6% (n = 841) of all trials and for exactly 50% (495 of 990) of all published studies.

Conclusions Fewer than half of neurology studies registered on ClinicalTrials.gov are published in a scientific journal, with rates varying among subcategories. Time to publication was consistent among subcategories, except “vascular neurology,” which had a significantly shorter time to publication. Further research can identify the source of variation such as journal niche, funding source, influential investigators, and research competition. Similar to other cross-sectional studies of this registry, further emphasis should be placed on result dissemination of registered trials including additional requirements and oversight.

1Department of Neurology, Yale University School of Medicine, New Haven, CT, USA, david.mampre@yale.edu

Conflict of Interest Disclosures: Dr Sheth has received research funding from Remedy Pharmaceuticals Inc, Stryker Clinical Research, and C.R. Bard Inc. Dr Ross receives research support through Yale University from Johnson and Johnson to develop methods of clinical trial data sharing, Medtronic Inc, the Food and Drug Administration to develop methods for postmarket surveillance of medical devices and to establish a Center for Excellence in Regulatory Science and Innovation at Yale and Mayo Clinic, Blue Cross Blue Shield Association to better understand medical technology evaluation, Centers of Medicare and Medicaid Services to develop and maintain performance measures that are used for public reporting, and Laura and John Arnold Foundation to support the Collaboration on Research Integrity and Transparency at Yale. Dr Ross reports that he is a member of a scientific advisory board for FAIR Health Inc. Dr Ross receive support from the Centers of Medicare and Medicaid Services to develop and maintain performance measures that are used for public reporting. Dr Ross is supported by grant K08 AG032886 from the National Institute on Aging and by the American Federation for Aging Research through the Paul B. Beeson Career Development Award Program. No other disclosures were reported.

Funding/Support: No external funding was provided for this study. Contributions for staff time and resources came from the Yale University Department of Neurology.